This first stage firing is part of a full launch dress rehearsal at the Space Launch Complex 40 at the U.S. Air Force Station at Cape Canaveral in preparation for the first Commercial Orbital Transportation Services (COTS) launch of the Dragon spacecraft. The rehearsal will exercise the countdown processes and end after the engines fire at full power for two seconds, with only the hold-down system restraining the rocket from flight.

After the test, SpaceX will conduct a thorough review of all data as engineers make final preparations for the upcoming launch.

Using rocket-grade kerosene and liquid oxygen, the nine Merlin engines generate one million pounds of thrust in vacuum. The Merlin engine is the highest performing American hydrocarbon rocket engine ever flown.

SpaceX uses a hold-before-release system "” a capability required by commercial airplanes but rarely implemented on launch vehicles. After the first stage engine ignites, the Falcon 9 is held down and not released for flight until all propulsion and vehicle systems are confirmed to be operating normally. An automatic safe shut-down will occur and propellants will be unloaded if any issues are detected.

SpaceX plans to launch its Dragon spacecraft into low-Earth orbit atop a Falcon 9 rocket. The Dragon capsule is expected to orbit the Earth at speeds greater than 17,000 miles per hour, reenter the Earth's atmosphere, and land in the Pacific Ocean a few hours later. This will be the first attempt by a commercial company to recover a spacecraft reentering from low-Earth orbit. It is a feat performed by only 6 nations or government agencies: the United States, Russia, China, Japan, India, and the European Space Agency.

It is also the first flight under NASA's Commercial Orbital Transportation Services program to develop commercial supply services to the International Space Station. After the Space Shuttle retires, SpaceX will fly at least 12 missions to carry cargo to and from the International Space Station as part of the Commercial Resupply Services contract for NASA. The Falcon 9 rocket and Dragon spacecraft were designed to one day carry astronauts; both the COTS and CRS missions will yield valuable flight experience toward this goal.

If launch is a go, SpaceX plans to broadcast the entire launch live at www.spacex.com between December 7th and 9th.